1. Field of the Invention
The present invention relates to the field of stabilising equipment for reducing unwanted motions of waterborne vessels. More particularly but not exclusively, it relates to such stabilising equipment mountable to small waterborne vessels, such as motorboats, cabin cruisers, and the like.
2. Description of the Related Art
Excessive motion of a ship, boat or other vessel in rough seas can lead to a range of problems. Passengers without good “sea-legs” may become sea-sick as a result of either regular or irregular motions of a vessel. More seriously, excessive motion of the vessel, whether pitching, yawing and/or rolling can lead to injury to passengers and crew, damage to cargo and to ship's equipment, and in the extreme case to loss of the vessel, for example by capsizing.
It has been known for some time that stabilisers can be fitted to reduce unwanted motions of ships, particularly of passenger vessels and ferries. Such stabilisers can be fitted during construction or during refit, and conventionally comprise fins or paddles extending outwardly from the ship's hull below the waterline. Such stabilisers are usually controlled to move actively to counteract predictable motions, such as rolling.
Such stabilisers increase the beam and/or draught of the vessel, as they need to project significantly outwardly beyond the hull to have significant effect. It is hence usually necessary for the stabilisers to be foldable against the ship's hull, or to be retractable inboard, particularly when a vessel is in restricted waters or is docking. This all requires complex and bulky operating mechanisms, occupying significant hull volume.
These stabilisers are hence complex and expensive, and do not scale down readily for use on smaller vessels, such as so-called “pleasure craft”, including cabin cruisers, motorboats and dinghies.
There is hence a need for a stabilising system that can readily be mounted to a range of small craft, optionally temporarily, without excessive/expensive refitting, which is effective in the water conditions likely to be encountered by such craft, and which does not affect the handiness, ease of docking, versatility and/or shallow draft of such small craft.